1bll
From Proteopedia
(New page: 200px<br /><applet load="1bll" size="450" color="white" frame="true" align="right" spinBox="true" caption="1bll, resolution 2.4Å" /> '''X-RAY CRYSTALLOGRAPHI...) |
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| - | [[Image:1bll.gif|left|200px]]<br /><applet load="1bll" size=" | + | [[Image:1bll.gif|left|200px]]<br /><applet load="1bll" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1bll, resolution 2.4Å" /> | caption="1bll, resolution 2.4Å" /> | ||
'''X-RAY CRYSTALLOGRAPHIC DETERMINATION OF THE STRUCTURE OF BOVINE LENS LEUCINE AMINOPEPTIDASE COMPLEXED WITH AMASTATIN: FORMULATION OF A CATALYTIC MECHANISM FEATURING A GEM-DIOLATE TRANSITION STATE'''<br /> | '''X-RAY CRYSTALLOGRAPHIC DETERMINATION OF THE STRUCTURE OF BOVINE LENS LEUCINE AMINOPEPTIDASE COMPLEXED WITH AMASTATIN: FORMULATION OF A CATALYTIC MECHANISM FEATURING A GEM-DIOLATE TRANSITION STATE'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The structure of the complex of bovine lens leucine aminopeptidase (blLAP) | + | The structure of the complex of bovine lens leucine aminopeptidase (blLAP) with the slow-, tight-binding inhibitor amastatin has been determined by X-ray crystallography. X-ray diffraction data were collected at -150 degrees C from a single blLAP-amastatin crystal which under the data collection conditions was of the space group P6(3)22 with unit cell parameters a = 130.3 A and c = 121.9 A. The structure of the blLAP-amastatin complex was determined by molecular replacement, using the structure of native blLAP as the starting model. Refinement of the blLAP-amastatin model plus 132 water molecules against data from 10.0- to 2.4-A resolution resulted in a final structure with a crystallographic residual of 0.198. The binding mode of amastatin is similar to that of bestatin, the structure of whose complex with blLAP has previously been determined. Of particular note, the N-terminus-to-C-terminus orientation of the two bound inhibitors is the same. The two N-terminal residues of amastatin and bestatin occupy the same binding sites, which are most likely S1 and S'1. The slow binding of amastatin and bestatin may be partially attributable to a binding mechanism in which the two active site metals are sequentially coordinated by the P1 amino and hydroxyl groups of these inhibitors. A catalytic mechanism for blLAP is proposed based on the binding modes of amastatin and bestatin and plausible binding modes of a dipeptide substrate and its putative gem-diolate transition state which were modeled into the active site of blLAP after the binding mode of amastatin. The proposed catalytic mechanism invokes roles for the catalytic metals in binding and activating the substrate and in stabilizing the transition state. The mechanism also includes roles for Asp-255 as a general base, Arg-336 as an additional electrophilic substrate activator and transition state stabilizer, and Lys-262 as a proton shuttle. |
==About this Structure== | ==About this Structure== | ||
| - | 1BLL is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/ ] with ZN and FOR as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Leucyl_aminopeptidase Leucyl aminopeptidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.11.1 3.4.11.1] Full crystallographic information is available from [http:// | + | 1BLL is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/ ] with <scene name='pdbligand=ZN:'>ZN</scene> and <scene name='pdbligand=FOR:'>FOR</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Leucyl_aminopeptidase Leucyl aminopeptidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.11.1 3.4.11.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1BLL OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Kim, H.]] | [[Category: Kim, H.]] | ||
| - | [[Category: Lipscomb, W | + | [[Category: Lipscomb, W N.]] |
[[Category: FOR]] | [[Category: FOR]] | ||
[[Category: ZN]] | [[Category: ZN]] | ||
[[Category: hydrolase(alpha-aminoacylpeptide)]] | [[Category: hydrolase(alpha-aminoacylpeptide)]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:56:35 2008'' |
Revision as of 09:56, 21 February 2008
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X-RAY CRYSTALLOGRAPHIC DETERMINATION OF THE STRUCTURE OF BOVINE LENS LEUCINE AMINOPEPTIDASE COMPLEXED WITH AMASTATIN: FORMULATION OF A CATALYTIC MECHANISM FEATURING A GEM-DIOLATE TRANSITION STATE
Overview
The structure of the complex of bovine lens leucine aminopeptidase (blLAP) with the slow-, tight-binding inhibitor amastatin has been determined by X-ray crystallography. X-ray diffraction data were collected at -150 degrees C from a single blLAP-amastatin crystal which under the data collection conditions was of the space group P6(3)22 with unit cell parameters a = 130.3 A and c = 121.9 A. The structure of the blLAP-amastatin complex was determined by molecular replacement, using the structure of native blLAP as the starting model. Refinement of the blLAP-amastatin model plus 132 water molecules against data from 10.0- to 2.4-A resolution resulted in a final structure with a crystallographic residual of 0.198. The binding mode of amastatin is similar to that of bestatin, the structure of whose complex with blLAP has previously been determined. Of particular note, the N-terminus-to-C-terminus orientation of the two bound inhibitors is the same. The two N-terminal residues of amastatin and bestatin occupy the same binding sites, which are most likely S1 and S'1. The slow binding of amastatin and bestatin may be partially attributable to a binding mechanism in which the two active site metals are sequentially coordinated by the P1 amino and hydroxyl groups of these inhibitors. A catalytic mechanism for blLAP is proposed based on the binding modes of amastatin and bestatin and plausible binding modes of a dipeptide substrate and its putative gem-diolate transition state which were modeled into the active site of blLAP after the binding mode of amastatin. The proposed catalytic mechanism invokes roles for the catalytic metals in binding and activating the substrate and in stabilizing the transition state. The mechanism also includes roles for Asp-255 as a general base, Arg-336 as an additional electrophilic substrate activator and transition state stabilizer, and Lys-262 as a proton shuttle.
About this Structure
1BLL is a Single protein structure of sequence from [1] with and as ligands. Active as Leucyl aminopeptidase, with EC number 3.4.11.1 Full crystallographic information is available from OCA.
Reference
X-ray crystallographic determination of the structure of bovine lens leucine aminopeptidase complexed with amastatin: formulation of a catalytic mechanism featuring a gem-diolate transition state., Kim H, Lipscomb WN, Biochemistry. 1993 Aug 24;32(33):8465-78. PMID:8357796
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